Armed pirates raided an oil tanker off the coast of Malaysia and took three crew members with them, Malaysian maritime officials said on Wednesday, underscoring increasing threats to shipping in one of the world's busiest waterways. The incident in the Malacca Strait, a route for about a quarter of the world's seaborne oil trade, has fueled fears piracy could be on the rise in the area and drive up ship insurance premiums. "We are very concerned," said Noel Choong, head of the International Maritime Bureau's Malaysia-based Piracy Reporting Centre, who added the ship was hijacked while sailing near the Malaysia town of Port Klang. "It's the first time this has happened so far north in the Malacca Strait, and the first time they have kidnapped the crew.